carte de séjour - change of status
I am a British citizen and hold a non actif one year carte de sjour cds.
I am in the process of setting up as a micro- entrepreneur but am yet to make first declaration of turnover as am still waiting for paperwork. Although I understand that I can, as an EU citizen, set up as an ME without a cds, since I already have one, do I need to apply to change the status of that card as soon as I have the requisite paperwork? I do not think I can do it yet- although I registered in April 2019 and have siret number I have only temporary social security number which means I cannot make first turnover declaration ( which is required in application for self employed cds).
Or since there is no actual legal requirement for me to hold a cds pre Brexit, do I wait until after Brexit and apply for the new 4 year card which I understand I will need to do anyway?
Thanks